1. Field of the Invention
The present invention relates to video cursor positioning systems. More particularly, the invention concerns a system for positioning a cursor on a video screen, in which pointing time and operator fatigue are reduced by integrating eye gaze tracking and manual operator input.
2. Description of the Related Art
In human-computer interaction, one of the most basic elements involves selecting a target using a pointing device. Target selection is involved in opening a file with a mouse "click", activating a world wide web link, selecting a menu item, redefining a typing or drawing insertion position, and other such operations. Engineers and scientists have developed many different approaches to target selection. One of the most popular target selection devices is the computer mouse. Although computer mouses are practically essential with today's computers, intense use can cause fatigue and repetitive motion injury.
Despite these limitations, further improvement of mouse-activated target selection systems has been difficult. One interesting idea for possible improvement uses eye gaze tracking instead of mouse input. There are several known techniques for monitoring eye gaze. One approach senses the electrical impulses of eye muscles to determine eye gaze. Another approach magnetically senses the position of special user-worn contact lenses having tiny magnetic coils. Still another technique, called "corneal reflection", calculates eye gaze by projecting an invisible beam of light toward the eye, and monitoring the angular difference between pupil position and reflection of the light beam.
With these types of gaze tracking systems, the cursor is positioned on a video screen according to the calculated gaze of the computer operator. A number of different techniques have been developed to select a target in these systems. In one example, the system selects a target when it detects the operator fixating at the target for a certain time. Another way to select a target is when the operator's eye blinks. One problem with these systems is that humans use their the eyes naturally as perceptive, not manipulative, body parts. Eye movement is often outside conscious thought, and it can be stressful to carefully guide eye movement as required to accurately use these target selection systems. For many operators, controlling blinking or staring can be difficult, and may lead to inadvertent and erroneous target selection. Thus, although eye gaze is theoretically faster than any other body part, the need to use unnatural selection (e.g., by blinking or staring) limits the speed advantage of gaze controlled pointing over manual pointing.
Another limitation of the foregoing systems is the difficulty in making accurate and reliable eye tracking systems. Only relatively large targets can be selected by gaze controlling pointing techniques, because of eye jitter and other inherent difficulties in precisely monitoring eye gaze.
Consequently, known gaze-based target selection systems are not adequate for some applications due to certain unsolved problems.